Location-based applications are new and exciting, but without a GPS device or an address, its difficult to figure out the location. Getting location from IP address is not reliable. For example, one IP-to-Address service reports that I am located in New Jersey although I am sitting at home located in the middle of SF peninsula. Within cellular networks, location can be found by triangulation but current cellular network throughput is a severe constraint for many location-based applications.
So I have been thinking that WiFi can be used to get approximate location (within ~300 feet). I know that there are new WiFi gears coming out that will extend the range to 1.2 miles, but it doesn't hurt to muse in case it leads to something interesting. With such a service, a WiFi station can provide the location information to the user as well as the party at the other end. One immediate application is stolen laptop retrieval. What else? Food for more thought.
[As I was writing this post, I searched google for information on destructive range of bombs because I was curious about how big a bomb is needed to ensure kill within 300 feet. I hope my curiosity doesn't put me on Home Security Department's radar. <g>]